Gas in Air Filter

[The Seldom One]

Very strong gas smell in the air filter compartment and the air filter. As far as I could tell there wasn't gas in the oil, which after doing some searching, seems to be an issue as well.

I read on a post somewhere that too tight of valves may cause this.
Also someone else had mentioned carb float height being in correct or bad valves being a potential cause.

I plan on checking my valve clearance tomorrow and adjusting if necessary.
If I can find a manual online that shows how to service the carbs, I may try and tackle that as well.


What could cause gas in the air filter?
Is there something else I should check out?

Thanks.

[Sirref]

If the bike has been on its side at all the air filter can take on oil/gas. This in addition to everything you've already listed as a possibility

[The Seldom One]

Originally Posted by Sirref

If the bike has been on its side at all the air filter can take on oil/gas

The bike hasn't been on its side at all. Other ideas?

[VaFish]

It just smells like gas? Or you are seeing puddles of gas n the air box?

[The Seldom One]

There is gas in the air filter, a small amount in the housing and a very strong smell.

I went to remove my gas tank, pet cock in the on position, and it leaked fuel.
Read it was a common issue, someone stated that they solved it by stretching the spring inside it. I stretched mine from.5 inch to .75 inch. Tested it and it worked.

I read that our bikes won't overflow the carb if the petcock leaks, I don't remember the reason. It was mentioned that if it does, there is either an issue with dirt, the float bowls leaking, the float height, or the float valves.

Removed the carbs and the float valves looked clean. They still have a very nice cone shape, both floats drop at the same time and are the same height, although I haven't checked if it is at the Correct height. I read it was supposed to generally be parallel with the carb. Also the little piston on the float valves push in and spring back with little resistance and do not stick. I assume thats how they are supposed to function?

I read in a thread that, "the most common malfunction is a leaky valve (the pushes up but the valve doesn't close completely). Valves can leak due to wear, stock debris, and dislocation from the proper position."

Questions:
Is there something else I should be looking for?

Could where the float valve seats in cause an issue?

Does anyone know of a way to test if the valve and float are functioning properly?
I was just going to submerge the floats to see if the leak.
Check the float height.
Clean the float valves, etc.

Any feedback is appreciated. Thanks.

Edit:
added a picture of the float valves.

When pressing in the float valves tiny piston, fuel bubbles out, is that normal?

[Triple Jim]

When I got my '05 250 last year, the petcock was leaking. I changed the little O-ring on the valve plunger and that fixed it. It's a #007 Viton O-ring. I had a pack of 100 that I got from McMaster-Carr years ago for a different motorcycle. Local industrial suppliers should have them or be able to get them cheaply. Stretching the spring might help an O-ring that's getting old and hard, but it's probably not going to fix the problem in the long run.

I'm used to being able to tell if float valves are leaking by watching the carb overflow tubes with the petcock open. I don't have much experience with the carbs on 250s yet, but I assume they have overflow tubes or the equivalent.

[RacinNinja]

Originally Posted by The Seldom One

There is gas in the air filter, a small amount in the housing and a very strong smell.

I went to remove my gas tank, pet cock in the on position, and it leaked fuel.
Read it was a common issue, someone stated that they solved it by stretching the spring inside it. I stretched mine from.5 inch to .75 inch. Tested it and it worked.

I read that our bikes won't overflow the carb if the petcock leaks, I don't remember the reason. It was mentioned that if it does, there is either an issue with dirt, the float bowls leaking, the float height, or the float valves.

Removed the carbs and the float valves looked clean. They still have a very nice cone shape, both floats drop at the same time and are the same height, although I haven't checked if it is at the Correct height. I read it was supposed to generally be parallel with the carb. Also the little piston on the float valves push in and spring back with little resistance and do not stick. I assume thats how they are supposed to function?

I read in a thread that, "the most common malfunction is a leaky valve (the pushes up but the valve doesn't close completely). Valves can leak due to wear, stock debris, and dislocation from the proper position."

Questions:
Is there something else I should be looking for?

Could where the float valve seats in cause an issue?

Does anyone know of a way to test if the valve and float are functioning properly?
I was just going to submerge the floats to see if the leak.
Check the float height.
Clean the float valves, etc.

Any feedback is appreciated. Thanks.

Edit:
added a picture of the float valves.

When pressing in the float valves tiny piston, fuel bubbles out, is that normal?

Best way to test those is to put them back in the carb along with the floats. Attach a clean piece of tubing to the fuel inlet and hold the cabs upside down so the floats press those needles closed. See if you can blow into the hose with the carbs upside down.

If you can, replace the needles.

If you can't, needles are good.

[The Seldom One]

@tripleJim
thanks for the advice. I will make sure I have some of this on hand incase the fuel petcock fails again. This is the first time I've dealt with a carburetor, nice to be learning something new, but not really knowing how they work makes solving this issue a pain.



@RacinNinja
Air cannot be blown through while doing what you said, and to make sure I was doing it right, I turned it right side up, and air flowed freely.

Edit:
My float heights were not the same, now I didn't use calipers, but one was .6875" and the other was .625"
The manual says .67" +- .08" is within spec. Would this warrant adjustment and maybe be the cause? I don't know how precisely I can bend those small metal tabs.